Constant-current dynamotor for individual arc circuits



Sept. 18,1923. 1,468,159

J. A. HOLIFIELD CONSTANT CURRENT DYNAMO'IOR FOR INDIVIDUAL ARC CIRCUITS Filed Sept. 26. 1921 J. 9. f/Ol/We/O.

Patented Sept. 18, 1923.

UNITED STATES PATENT OFFICE.

JOSEPH A. HOLIFIELD, OF MOBILE, ALABAMA, ASSIGNOR TO WHITE FUEL OIL EN- GINEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

CONSTANT-CURRENT DYNA-MOTOR FOR INDIVIDUAL ARC CIRCUITS.

Application filed September 28. 1921. Serial No. 503,216.

T 0 all whom it may concern. I

Be it known that I, Josnrn A. Hourmno, a citizen of the United States of America, residing at Mobile, in the county of Mobile and State of Alabama, have invented .certain new and useful Improvements in Constant-Current Dynamotors for Individual Arc Circuits, of which the following is a specification.

My invention relates to a dynamotor generator and regulator for individual arc circuits having for its principal characteristic inherent automatic regulation which produces a variable voltage but maintains a substantially constant current in the arc, which regulation is governed by the variable resistance in the arc.

My invention differs from that class of dynamotors which are designed and connected for the purpose of producing a constant voltage and variable current, which current may be maintained substantially constant by the interposition of a variable resistance in the arc circuit. The advantage of my arrangement over welding outfits of such a character consists essentially in two features, namely, that I produce a self contained automatic regulating unit which dispenses with the requirement of any re sistance regulator or any external current regulator for the arc circuit, and I obtain a much more constant current at the are, a tougher arc and a deeper penetration and therefore a more perfect bond in the welds.

In my companion application, Serial No. 454,277, filed March 21st, 1921, I have shown and described a self regulating arc current generator which was intended to be driven with a constant speed motor and when so driven it would generate an arcing current having a variable Volta and a constant current characteristic at t e arc.

My chief object is to produce a simple self contained dynamotor for individual are circuits that embodies the great economy of the variable voltage are system described in my said application, while at the same time obtaining the high efiiciency well known in the dynamotor, with low first cost and light wei ht.

y invention is applicable to the generation and re lation of current for a motion picture pro1ecting arc and for any other use requiring a constant current and variable voltaL'e at the work.

In designing my dynamotor I employ twin poles which are so wound as to induce by the sum of their magnetic influence a current flow in the armature proportionate to the requirements at the arc and capable of instantaneous change to accommodate itself to variations of resistance in the arc. It is of vital importance, in obtaining the instantaneous regulation, that this should be obtained independently of external regulators and as a result of magnetic influences which are directly responsive to the arc and which control the generation of current in the dynamotor. More sim ly expressed, my a paratus contemplates utilizing the arc to dlrectly draw from the source of electrical energy that which is required to maintain it at highest efficiency and is in contra-distinction to those systems which generate the current and then by separate agencies control its delivery to the arc.

While my invention is apable of various a twin pole dynamotor with its regulating set of fields compound'wound.

Fig. 2 is a similar view showing a modification of the compound windings of the regulating set of fields, a separately excitin boosting shunt coil being here used.

ig. 3 is a view of a modification 1n which the power circuit is straight connected through the generator field and armature to the line.

Similar reference numerals refer to similar parts throughout the drawings. a

In the embodiment illustrated in Fig. 1, 1 is the positive main line feeder which branches part of the current passing over a circuit 2 through the coil 3 about the constantly excited pole 4 and returning to the negatlve main line 5. The, other branch of armature brushes 6 and 7 and continues along the circuit 8 to the work 9. The manually movable welding electrode 10 is connected by a circuit 11 to the negative main line 5. The current flowing in circult 8 branches at 12, one circuit 13 be1ng connected across the armature brushes 14 on the generator side and thence passing 1n series through the differential compound COll 15 surrounding the pole 16 and thence returning to the-circuit 5. The other branchcircult 17 leads in series to the coil 18 about the pole piece 16 and then connects at 19 w tha c1 rcuit 2O branching from the positive main line 1 at 21 and connected to the negative main line, and in this circuit 20 on opposite sides of the connection point 19 I 1nterpose resistances 22 and 22.

The armature comprises a motor commutator 23 with which the brushes 6 and 7 coact and a generator armature 24 with which the brushes 14 co-act. The windings 25 from the generator commutator pass under both sets of poles at and 16 while the windin s 26 for the motor commutator extend only under the constantly excited set of poles 4.

Under open circuit conditions, the main line current flows to 21 where it branches, a small part flowing through the resistances 22 and 22 and back out over the negative line 5, and part continues to the branching point for the circuit 2 where it again divides part flowing through the constantly excited field coils 3 and returning to the negative main line, and the other part or main current flowing across the motor brushes to circuit 8 and at 12 it again branches, part flowing across the dynamo brushes 14 and through series coil 15 of the variably excited regulating fields and returning to the negative line 5, and part flowing over circuit 17 through the coil 18 of the regulating fields to the circuit 20 at 19 and thence through the resistance 22 to the negative line 5. The resistance 22 is suf ficient to shunt the desired percentage of the current from direct fiow through the circuit 20, diverting it through the circuit 17 as described.

The coils 15 and 18 are wound so that they will always, under open circuit conditions, generate in the armature windings 25 a current which will boost the current generated by the constantl excited coil 3. On striking the arc, the ollowing changes in the flow of current at once takes place, namely, the main line current instantly changes its course to the path of lowest resistance and flows direct to the arc and out through circuits 11 and 5. The shunt flow of current through the field 3 remains always constant. The circuit 13, which was used as part of the motor circuit, now forms a local generator circuit in which the flow of current is reversed in the coil 15 and the current enerated is delivered at 12 collectively with the main line current flowing over the circuit 8 to the arc. The result of this reversal flow of current in the coil 15 is to convert this into a bucking field which now opposes the field 3 producing magnetism that will buck the constant magnetism produced by the poles 4, thereby setting up a bucking counter-electro motive force in the generator windings which controls the current output of the generator. The flow of the current in the circuit. 17 also becomes reversed because the short circuit at the are will stop the flow of currentin' the circuit 17 in the direction of its flow under open circuit conditions because of the low resistance between its connection point 12 through the arc to the return circuit 5, the effect of the resistance 22, and the counter-electro motive force of the motor which latter will shunt a portion of the current past resistance 22 in circuit 20 to the junction point 19 where it will be divided, part flowing through the resistance 22 to the negative line 5 and part through the circuit 17 to the arc. This results in a reversal of current flow in the coil 18 so that it now boosts the coil 15 and bucks the field 3, thus both windings of the variable set of poles 16 are now bucking the constant fields 3 and they thus restrain, with their counter-electro motive force, the generation of current in the armature coils 25 in direct proportion to the variation in the resistance in the arc itself, as this resistance controls directly and instantaneously the magetic intensity of the bucking fields 15 and 18. I thus maintain a constant current within normal limits of the arc, the voltage varying according to the requirements of the arc.

In Fig. 2 all the circuit connections are the same as in Fig. 1, except, in place of the reslstance circuit 20 I interpose a simple shunt circuit 26 leading from the main line at 27 and connecting in series with the coil 18 and returning to the negative line wire 5 over the wire 2. In this arrangement the field 18 is always constantly energized in the same direction under both open and closed circuit conditions and its magnetic influence is always exerted to boost the coil 3. There will be a reversal. of the flow of current through the field coil 15 as already described when the arc is struck, and as a result the coils 15 and 18 will buck each other and as the coil 15 will predominate the result of its magnetic influence will be to buck that of the coil 3. As the resistance at the arc increases, the field 15 weakens and its predominance over the coil 18 falls, so thatthe voltage and current output of the dynamotor increases in proportion to the requirements at the are.

In Fig. 3 the main line circuit entering over the wire 1 flows across the motor brushes 6 and 7' and returns directly to the negative line wire 5.. The circuit 2 feeds both the coils 3 and 18, returning direct to the negative line wire 5. The generator brushes 14 are connected in a separate arc circuit 28 which comprises in series therewith the bucking field coil 15. In this arrangement the arc is supplied wholly by the generated current in the circuit 28 and the current flow is at all times directly responsive to the difference in magnetic intensity between the buckin twin fields of the dynamotor. As, the resistance increases at the arc, the intensity of the coil 15 weakens and thus the constantly excited coil 3 tends to further predominate, thus increasing the current flow generated in the armature in exact proportion to the requirements at the arc, and since the regulating function is derived from a rise or fall in the current flow of the arc circuit it follows that the response of the regulation will be instantaneous and proportional to the arc requirements.

It is the essence of my invention that the twin fields of the dynamotor shall be so wound and connected that variations in resistance at the, arc will control the degree of the predominance of the constantly excited fields over the variably excited fields and this obviously may be accomplished in a variety of ways other than that described, and applied to a variety of other uses than have been stated.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is: I

1. A mechanism for the generation and regulation of electrical current for a single arc circuit comprisin in combination with the circuit including t e are and a, main supply circuit, a dynamotor comprising twin' fields having a single armature with its generator windings extending under both fields and its motor windings extending only under one field, a branch, circuit from the main supply circuit to constantly energize said latter field, and circuit connections to produceinthe other field, when the arc circuit is closed, a magnetism counter to that of the constantly energized field and varying in direct proportion to the resistance in the arc.

2. A mechanism for the generation and regulation of electrical current for an arc circuit, according to claim 1, in which the pole pieces for the twin fields are adapted to span substantially the same enerator windings on the armature, where y the dynamotor is inherently regulated tolary the voltage thereof in accordance with the resistance at the arc. I

In testimony whereof, I afiix my signature.

' JOSEPH A. HOLIFIELD.

Witness:

Noun: Wnnsn. 

